1. Technical Field
The present invention generally relates to resistive touch systems and, particularly to a resistive touch controlling system and sensing method can perform zoning scanning.
2. Description of the Related Art
A resistive touch control screen is a type of most popular touch control technologies, and its driving principle is using a voltage drop to calculate a coordinate. That is, a plurality of X and Y axes each are applied with voltages for driving. When the resistive touch control screen is touched, since a loop is turned on, voltage drops would be correspondingly generated, and a controller would calculate out occupied proportions of the respective voltage drops and then calculate out coordinates.
When the resistive touch control screen is touched or approached, coordinates of a touch point can be determined according to an intersection between an X axis and a Y axis which respectively generate voltage drops. More specifically, when scanning all the X axes, it only can acquire a scanning result of a certain one X axis generating a voltage drop. Similarly, when scanning all the Y axes, it also only can acquire a scanning result of a certain one Y axis generating a voltage drop. Therefore, if wanting to determine the coordinates of the touch point, it is necessary to combine the two scanning results obtained by scanning the X axes and the Y axes.
However, such conventional method would not cause misjudgment in the situation of single touch, but is not suitable for the operating environment of multi touch. Taking two touch points as an example, when coordinates of actual touch points are (X1, Y2) and (Y1 X2), in examining a scanning result of scanning the X axes, it would be found that the X1 axis and the X2 axis generate voltage drops, and in examining a scanning result of scanning the Y axes, it would be found that the Y1 axis and the Y2 axis generate voltage drops. The calculated touch coordinates according to the two scanning results would include (X1, Y1), (X2, Y2), (X2, Y1) and (X1, Y2). Where, only coordinates (X1, Y2) and (X2, Y1) are coordinates of the actual touch points, while the coordinates (X1, Y1) and (X2, Y2) are so-called ghost points and are not the coordinates of actual touch points. Accordingly, an appropriate method to eliminate the existence of ghost points is necessary in the resistive touch controlling system, so as to avoid the occurrence of confusion in determining the coordinates of touch points and causing the failure of coordinate determination.